MICROANATOMY

MUSCLE NERVE CARTILAGE BONE

SKELETAL MUSCLE

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
the functional contractile unit within a muscle fiber is called the
A
sarcomere
B
fascia
C
sarcoplasm
D
tendon
Explanation: 

Detailed explanation-1: -A sarcomere is the basic contractile unit of a myocyte (muscle fibre). A sarcomere is composed of two main protein filaments (thin actin and thick myosin filaments) which are the active structures responsible for muscular contraction.

Detailed explanation-2: -A sarcomere is the functional unit (contractile unit) of a muscle fiber. As illustrated in Figure 2-5, each sarcomere contains two types of myofilaments: thick filaments, composed primarily of the contractile protein myosin, and thin filaments, composed primarily of the contractile protein actin.

Detailed explanation-3: -The sarcomere is the fundamental contractile unit of the myofibril.

Detailed explanation-4: -To say that the sarcomere is the functional unit means that all the components needed for contraction are contained within each sarcomere. In fact, muscle is composed of millions of tiny sarcomeres, and each sarcomere shortens, thus resulting in muscular contraction.

Detailed explanation-5: -The fundamental repeat unit within muscle that is responsible for contraction is the sarcomere. The sarcomere consists of a bundle of myosin-containing thick filaments flanked and interdigitated with bundles of actin-containing thin filaments (Fig. 1).

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